Griseofulvin, an antibiotic obtainable from at least four kinds of Penicillium, has been found effective in certain experimental fungous infections of animals as well as in fungous diseases of man. It was used in 200 patients with superficial fungous infections at 311 sites of major involvement. The organism most frequently found was Trichophyton rubrum, identified in 185 sites. The dosage of griseofulvin varied from 0.5 to 1.0 Gm. by mouth. One gram per day is recommended. When the lesions did not involve the nails, palms, or soles, three weeks of therapy usually was adequate. Even with lesions of the palms and soles, relief from itching occurred in two to six days; vesicles and scales disappeared and cultures usually became negative in two to six weeks. It was necessary to keep in mind the fact that nails grow slowly and that the fungous infection may be superposed on other disease. Until more experience with this drug accumulates, monthly blood counts are advised, but in this series no significant manifestations of toxicity were noted.